Visualising Latent Fingermarks with Pure Organic Persistent Luminescent Materials

This past decade, organic persistent luminescent materials have gained considerable research interest and have been utilised by a diverse range of scientific disciplines. Here in this research, two organic persistent luminescent materials have been investigated, optimised, and prepared as fingerprint powders. Both powders were used as latent fingermark developers, following Phase 1 and 2 trials established by the International Fingerprint Research Group. The first organic persistent luminescent material,(3-Bromopropyl)triphenylphosphonium bromide, was selected from a recent publication and its photoluminescent properties were optimised. The second material investigated was 2,4,6-tri(4-pyridyl)-1,3,5-triazine. To the best of our knowledge, this is the first report which claims to have achieved a persistent luminescence in, 4,6-tri(4-pyridyl)-1,3,5-triazine, without the need of inorganic doping systems. Phase 2 trials identified both powdered materials to effectively develop latent fingermarks on non-porous surfaces, with (3-bromopropyl)triphenylphosphonium, performing slightly better out of the two. In summary, this study has identified the use of alternate organic persistent luminescent materials to be used as fingermark developers, and, with further investigations, may promise effective, low-cost alternatives to the persistent luminescent fingerprint powders currently on the market.